India’s Guillain-Barré Syndrome outbreak lays bare the dangers of water contamination

A surge of Guillain-Barré Syndrome (GBS) cases in India has raised alarm, underscoring the need for a unified One Health approach to tackle public health crises. The outbreak —centered in Pune but spreading across Maharashtra, Andhra Pradesh, Assam, Tamil Nadu, and West Bengal — has killed 23 people this year, with more than 200 reported cases.

The outbreak prompts questions about the role of environmental contamination in triggering neurological disorders and, more broadly, about India’s preparedness to tackle such public health threats.

A neurological disorder with an unexpected source

GBS is a severe neurological disorder in which the body’s immune system mistakenly attacks its own nerves, leading to weakness, paralysis, and, in extreme cases, respiratory failure. Diagnosis is challenging as symptoms are similar for other neurological conditions, and clinicians often rely on clinical features and tests to diagnose GBS¹. While many patients recover, some require critical interventions such as plasmapheresis and immunoglobulin therapy.

But the real story behind this outbreak is the water. A significant number of GBS cases develop after bacterial or viral infections. One of the most well-known triggers is Campylobacter jejuni, a bacterium that causes gastroenteritis and is the world’s biggest driver of GBS. The bacterium has been implicated in the Pune outbreak.

Endemic in most parts of the world, C. jejuni is a zoonotic pathogen, which can enter the food chain through undercooked poultry, unpasteurized dairy, and contaminated water sources. While infections with C. jejuni are typically self-limiting, in some cases, the immune response goes awry—leading to GBS. This happens when the antibodies generated to fight the infection mistakenly attack the gangliosides that cover peripheral nerves, leading to axonal degradation and demyelination, and eventual paralysis.

Similar outbreaks have occurred worldwide. In 2023, Peru declared a health emergency after a C. jejuni-induced GBS outbreak². In Brazil, Zika and chikungunya viruses have been linked to spikes in GBS cases³. A study by the National Institute of Mental Health and Neurosciences (NIMHANS) found that between 2014 and 2019, nearly 80% of GBS cases in India were preceded by infections — most commonly with the chikungunya virus⁴. Without a comprehensive surveillance system that integrates human, animal, and environmental health data, such outbreaks will continue to blindside public health officials.

A water crisis with far-reaching consequences

The outbreak in Pune has once again highlighted the dangers of contaminated water, a recurring public health threat in India. Investigations suggest that C. jejuni may have entered the water supply through sewage contamination, including infiltration into reverse osmosis (RO) systems. This is not an isolated case. Globally, previous outbreaks linked to C. jejuni have been traced to inadequate water treatment, and localized flooding events that allowed contaminated surface water to infiltrate groundwater sources⁵.

The implications go beyond GBS. Waterborne gastroenteric infections impose a heavy burden on public health, leading to widespread illness, lost productivity, and significant economic costs. According to a World Bank report, the annual global cost of treating foodborne illnesses exceeds $15 billion. The Pune outbreak is a stark reminder that food and water safety are not merely regulatory concerns. They are central to health security.

The One Health imperative

Faced with such an outbreak, a One Health approach is essential. One Health recognizes that human health is intricately linked to animal and environmental health⁶. A robust public health response to outbreaks like this must include coordinated surveillance across multiple sectors, from agriculture and veterinary medicine to environmental science and human healthcare.

This is precisely where India faces its greatest challenge. While the country has made progress in adopting a One Health framework, implementation remains fragmented. Strengthening environmental monitoring, enforcing stricter food safety regulations, and ensuring proper sanitation infrastructure are all critical steps. But beyond these, India must invest in cutting-edge tools for outbreak surveillance.

One such tool is whole-genome sequencing (WGS), which allows scientists to trace the source of an outbreak with unprecedented accuracy. WGS can determine the precise strain of C. jejuni responsible for an outbreak—an important distinction, as not all strains of the bacterium cause GBS. The World Health Organization (WHO) strongly recommends WGS for foodborne outbreak investigations, yet its adoption in India remains limited due to high costs, lack of infrastructure in rural areas, and shortages of trained personnel.

A global threat

India is not alone in facing these challenges. Across the world, public health systems are struggling to keep pace with the increasing frequency of zoonotic disease outbreaks. Climate change, urbanization, and the intensification of agriculture have all created conditions that allow pathogens to spread more easily between animals and humans. In this context, the WHO’s continued involvement in aiding India’s response to the Pune outbreak has reinforced the agency’s central role in tackling health crises.

Ultimately, the responsibility for protecting public health lies with national governments. India cannot afford to treat outbreaks like this as isolated incidents. Instead, it must take proactive steps to strengthen its One Health surveillance system, improve early detection of food and waterborne pathogens, and enhance intersectoral coordination.

This entails strengthening monitoring of environmental contaminants, measures to include agricultural remediation, promotion of safe animal agriculture practices, a consideration of socio-cultural factors that influence human-animal contact, ensuring adequate food safety practices, and a strict adherence to water, sanitation, and hygiene (WASH) management protocols⁷.

Whole-genome sequencing (WGS) is the gold standard technique advised by the WHO to address food-borne outbreaks with a One Health perspective. This enables attribution of the source including determining the type of strain, particularly since not all strains of C.jejuni cause GBS, and aids in identifying the source and magnitude of the outbreak⁸. Challenges for India in monitoring these outbreaks are the high cost associated with WGS, infrastructural support in rural settings, trained scientific personnel, and integration with the country’s One Health surveillance measures⁹.